From January to June, the total number of foreign visitors, including business travelers and residents, entering China declined by 5 percent to just under 13 million compared with the same period last year, according to the China National Tourism Administration. Overall, visitors from Asia, Australia, Europe and the Americas all declined.

In Beijing, with major attractions including the Great Wall and the Imperial Palace, the drop is even more striking. The number of foreign tourists visiting the Chinese capital fell by 15 percent in the first six months of the year to 1.9 million, according to the Beijing Tourism Administration.

Wide-spread reports of insane smog levels in Beijing earlier this year certainly didn't help its image. So for China -- which brings in the third-most international tourists in the world, making international tourism a $48 billion industry -- it looks like it will take an massive effort. But, if the Olympics are any indication, reversing the smoggy image of China is possible.